Ripping

Ripping is a deep pass with a steel shank pulled through the ground to crack a compacted layer without turning the soil. Traffic and rain pack a band of subsoil so tight that water ponds above it and roots turn sideways instead of down. The shank shatters that band, and water, air and roots follow the crack down. Cut along the contour, each line also catches water running over the surface and holds it to soak in.

The hard layer has to be found, not assumed. Dig and look at the roots: where they turn flat instead of down, something is stopping them. A penetrometer, a probe that measures soil resistance, gives the depth exactly, but only in soil wetted a day or two before. Compaction often sits only in headlands and wheel tracks, so mapping first saves fuel. Depth decides the tool: a shallow pan is handled by a no-till drill or a chisel plough, and only a restriction at 25 to 30 cm (10 to 12 in) or deeper needs a subsoiler, cutting at least 2.5 cm (1 in) below it. The whole depth of cut must be dry and crumbly: dragged through moist subsoil the shank polishes the pan instead of breaking it, sealing it tighter.

The fracture does not last. Rainfall alone accounts for most of the closing, and without controlled traffic, ripped ground has measured back at the density of ground never ripped. So it pays only alongside controlled traffic, light ground pressure, and something living in the crack - a deep-taprooted cover crop such as alfalfa or forage radish, or a crop sown into the line. The gain is largest on coarse soils with a shallow restriction; on clay it is smaller, and the pass can leave a new compacted layer below its working depth. It is costly in fuel and pulling power and must be repeated, so ground that keeps needing it has an upstream fault. The same tool run off contour is keyline plowing, which moves soil moisture across a slope instead of relieving compaction.